Sail-boom.



No. 879,986. PATENTED 513.25, 1908.

P. TATGHELL.

SAIL BOOM.

APPLIOATION FILED JULY 2, 1906.

4 SHEETS-SHEET 1.

No. 879,986. PATENTED FEB. 25, 1908.

- P. TATOHELL.

SAIL BOOM.

APPLICATION FILED JULY 2,1906.

4 SHEETS-SHEET 2.

No. 879,986. PATENTED FEB. 25, 1908. P. TATGHELL.

, SAIL BOOM.

APPLIOATION FILED JULY 2, 1906.

4 SHEETS-SHEET 3.

PATENTED FEB. 25, 1908. P. TATGHELL.

SAIL BOOM.

v APPLICATION FILED JULY 2, 1906.

4 SHEBTSSHEET 4.

PERCY TATOHELL, OF LONDON, ENGLAND.

SAIL-BOOM.

Specification of Letters Patent.

Patented Feb. 25, 1908.

Application filed July 2. 1906. Serial No. 324.484.

To all whom it may concern:

Be it known that I, PERCY TATCHELL, a subject of the King of Great Britain, residing at 73 Holland Park, in the county of London, England, gentleman, have invented certain new and useful Improvements in Sail-Booms, of which the following is a specification, reference being had to the drawings hereunto annexed and to the figures and letters marked thereonthat is to say The invention relates to improvements in or connected with sail-booms and the object thereof is to obtain a suitable lateral curvature in the boom and at the same time to brace the same in such manner that it will be strengthened or stiffened.

It is now a generally accepted theory that a certain amount of belly in a mainsail of fore and aft vessels is advantageous in certain conditions of wind, and when sailing to windward, and the best results are obtained by varying this belly according to the strength of the wind and diminishing it as the wind increases in force. This has to some extent been accom lished by cutting the sail rather full at the fore part or luff so as to obtain a certain amount of belly or flow which should, it is generally conceded, take the form of a parabolic curve.

Now according to the present invention the sail is cut with little or no belly or flow and is laced or otherwise fastened to the boom and the necessary belly or curve is imparted to the sail by bending the boom laterally to the required degree to give the best results under the conditions of wind prevailing.

In the accompanying drawings, Figure 1 is a side elevation of the main boom and part of the mast of a vessel, illustrating the application of the present invention to the main boom and showing the same in its normal condition. Fig.2isaplanthereof. Fig.3 is a transverse section taken on the line 11 of Fig. 1. Fig. 4 is aplan of Fig. 3. Fig. 5 is a transverse section taken on the line 22 of Fig. 1. Fig. 6 is a transverse section taken on the line 33 of Fig. 1. Fig. 7 is a transverse section taken on the line 1- of Fig. 1. Fig. 8 is a similar view to Fig. 2 but showing the boom in its bent condition. Fig. 9 is a similar view to Fig. 8 illustrating a slight modification. Fig. 10 is a transverse section taken on the line 55 of Fig. 9. Fig. 11 is a transverse section taken on the line 66 of Fig. 9. Fig. 12 is a transverse section taken on the line 7-7 of Fig. 9. Fig. 13 is a similar view to Fig. 8 illustrating a further slight modification. Fig. 14 is a side elevation of part of Fig. 13. Fig. 15 is a similar view to Fig. 1 illustrating a further modification. Fig. 16 is a plan thereof but showing the boom in its bent condition. Fig. 17 is a similar view to Fig. 1 illustrating the application of the invention to a balanced lug sail and Fig. 18 is a plan thereof showing the boom in its bent condition.

In the several figures like parts are indicated by similar letters of reference and Figs. 3 to 7 and 10 to 12 are drawn to an increased scale with respect to the other figures of the drawings.

Referring to Figs. 1 to 8, (it represents the deck of a vessel, 1) represents the mast and -0 represents the main boom. The boom 0 is assumed to be solid and to be constructed of wood but it will be obvious that it might be hollow and if desired constructed of metal or other suitable material and it may be of any suitable transverse section.

In the example given the boom is of a gradual taper from end to end, the smaller and lighter part being at the fore end or neck, and the larger and heavier part at the outer extremity, being at the after end, and it is shown to be of a flattened section, as that is preferable for the purpose of the invention, although it may be of any other suitable section. Transversely of the boom 0 and near or toward the fore end or neck thereof are arranged so as to project horizontally from each side thereof two struts d preferably carried by a band or collar (1 clamped around the boom in the well known manner or the struts 01 might be fixed with the boom 0 in any other suitable manner and. the extremities of the struts d are forked or notched, and if desired, furnished with sheaves or runners d as shown. Or instead of employing only one pair of struts 61 two pairs might be provided as hereinafter shown and described with respect to the subsequent figures or more than two pairs of struts might be employed if desired.

In connection with the strut d on each side of the boom 0 is employed a stay 6 consisting of a length of wire rope or it might be of other rope, chain, rod metal or the like and this stay 6 is by one end made fast to an eye arranged at one side of the boomv c and carried by a cap or it might be any other suitable fitting upon the after end of the boom 0. The

- be improved.

stay 6 is then carried across the sheave or the like 01 at the extremity of the strut d on one side of the boom and the other end thereof is made fast to a tackle or purchase 9 fastened to an eye h carried by a fitting h upon the fore end of the boom 0. The corresponding stay e upon the opposite side of the boom is similarly arranged and provided with similar tightening means and similarly operated. By hauling upon the fall 9 of the tackle g on one side of the boom and somewhat slacking the other fall any desired curvature within certain limits may be given to the boom the preferred curvature being parabolic and it may be fixed at that curvature by belaying the fall g of the tackle upon a cleat a fastened to the deck a while by subsequently and similarly tightening the stay e on the other or convex side of the boom 0 the latter will be efficiently braced or stiffened and a strong support given thereto.

The effect of the curvature of the boom will be to impart the required fullness, hollow or belly to the sail at or near the luff so that theoretically its propulsive power will When the vessel goes about on another tack the opposite curvature must be given to the boom 0 by manipulating the tackles g in the manner hereinbefore described.

In the example given at Figs. 9 to 12 the boom 0 is formed for part of its length of a cross shape section in order to give additional strength thereto and instead of providing the boom with one pair of strutsd two pairs thereof are employed. The tightening devices in this case are shown to consist of rigging screws 9 of the ordinary character which are manipulated in the ordinary way.

In the example givenin Figs. 13 and 14 the boom c is assumed to be of similar section to that hereinbeforeshowii and described withrespect to Figs. 1 to 7 but in this case j theends of t he s t ays e are led over guide pul' leys o r sheaves h carried by the fitting It under guide pulleys 72 3 upon the deck a and thence to a winch g. fixed to the deck a and provided with the usual pawl: so that by turning. the winch in either direction one stay e will be tightened and the other slackened in the desired manner. In this case rigging sc ews ar nter b d th th of h staysc dafiord anadjustment thereof with rela tionito thewinch g. 1

In the example given-at Figs. 15 and 16 the arrangement is substantially thesaine as that lastly hereinbefore described but a further. modification the means of hauling on the, stayse is' shown. The ends of the sta e are in this case as in the last preceding-ex ample passed around guide pulleys 7L2 b the- I latterbeing fixed upon the floor d of the boat but instead ofv being led to a winch they are passed around guide pulleys or sheaves k also fixed upon the floor a of the boat and fastened at g to a lever g at one end mounted upon a pivot 9 carried by the fioor a of the boat or it might be in other convenient position and working over a segmental rack g adapted to fix the lever g in any desired position. By moving the lever over the rack g in one direction or the other one, stay 0 will be tightened and the other slackened in a similar manner to that described with respect to the last preceding example.

In the example given at Figs. 17 and 18 the invention is shown applied to the boom of a balanced lug sail. The tackles g in this case are dispensed with and the ends of the stays e are passed around guide pulleys or sheaves 7L upon the boom 0 thence over similar pulleys or sheaves 713* upon the boom and thence under guide pulleys or sheaves h upon the deck a into a convenient position for hauling and tightening by hand or otherwise.

Although the invention has been hereinbefore described in connection with the main boom of a sailing vessel it will be understood that it is also applicable to other spars where a curve or belly to the sail would be an advantage and it will also be understood that the curved spar is useful for other purposes such for example as the construction of the and in what manner the same is to be per formed I declare that what I claim is 1. The combination with a sail-boom, of

means for curvingthe. boom laterally to imipa'r t belly tothe sail} said means comprising a stay secured to one end of the boom, means boom and mea ns for tightening or slackening said stay.

2Q The combination With a sail-boom, of

means fo r; curving the boom laterally to impart belly to the sail; said means comprising astay secured to one end'of the boom,- means connected to the; other ends of the stay for tighteningv or slackening the stay; and a lateralstrut on i the boom loosely engaging {the stay forfprojecting'the stay from the 3Q The combination witha'saihbooni", of meansfor curving the boom laterallyto impart belly to the; sail said eans compristending laterally from theboom andleo'sely engaging thefs tays for projecting the' stays from the boom and means connected to the slackening the stays.

'for' projecting'l the stay laterally from the 'ing a pair of stays secured toone end ofthe" boom Tat opposite' si'des--thereof, neans ex fotheriends of the stays for tighteningt' r 4. The combination with a sail-boom, of mechanism for curving the boom laterally to impart belly to the sail; said mechanism comprising a pair of stays having one end secured to the boom at opposite sides thereof, means for projecting the stays laterally from the boom and means connected to the other ends of the stays for tightening or slackening the stays and constructed to slacken one stay when the other stay is tightened.

5. A sail-boom of gradually tapering form from its outer to its inner end and provided With means for curving the boom to impart belly to the sail.

6. A sail-boom of substantially uniform height throughout its length and of gradually decreasing Width from its outer to its inner end.

In Witness whereof I have hereunto set my hand in the presence of two Witnesses.

PERCY TATCHELL.

Witnesses:

EDWARD ROBERT TAToHELL, FRANK TATCHELL. 

